March 2015

Stronghold

I think we all remember what the conclusion was after the last freezing season (see 2011/2012 Winter analysis): sea ice on the Atlantic/Siberian side of the Arctic looks vulnerable, sea ice on the Pacific/North American side should be thicker. So far there has been a very clear confirmation of the first half of this conclusion, in that the ice on the Atlantic side of the Arctic, along the Siberian coast, has retreated very fast, perhaps even faster than last year. This comparison I made a couple of days back (for the Fringe Fries 2 blog post) shows it well. For a more recent comparison I refer you to the Concentration Maps page on the ASI Graphs website.

I now want to take a look at how the ice on the other side has been doing so far. The Pacific/North American side basically consists of three regions: the Canadian Archipelago, the Beaufort Sea and the Chukchi Sea. In last month's blog post concerning the Northwest Passage it became clear that the Canadian Archipelago was mostly filled with first-year ice, but because of a relatively cold freezing season the ice was probably a bit thicker. The ice in the Northwest Passage and the rest of the Archipelago has been holding up pretty well, better than in previous years (as confirmed by the MASIE extent graph), but due to high temperatures and quite a bit of insolation in the last couple of weeks, the NWP now seems to be breaking up from the inside out. As the fast ice in Nares Strait broke up 10 days ago and ice transport from the Arctic Basin is about to start, I don't think the ice in the NWP is going to hold out much longer.

Because the Chukchi and Beaufort Seas are neighbours, I have made this comparison of University of Bremen sea ice concentration maps on July 7th in the 2004-2012 period, showing both regions (click for a larger version):

This year's ice in the Beaufort Sea clearly isn't any stronger than it was in previous years. We had already received a hint when the NSIDC released ice thickness data from IceBridge flight missions over parts of the Beaufort Sea, and the current big polynya and very low ice concentration there seem to confirm that this region isn't going to put a brake on this year's melt. But the region right next to it, the Chukchi Sea, just might.

It's obvious from the image above that 2012 is quite a bit behind record years 2007 and 2011. This NSIDC/NIC regional extent graph is showing the same:

Actually I'm a bit surprised that the sea ice area decrease in the Chukchi Sea hasn't progressed as much as in other years. Here's a comparison panel of the Chukchi Sea region from June 13th from the first Fringe Fries post. In most other years the edge of the ice pack has moved close to or past Wrangel Island, but this year the island is still well surrounded by ice.

In itself this isn't definite proof of anything, but it could be an indication that the ice here is thicker and stronger. Or it could mean that the sea surface temperatures are particularly low, sparing the ice at the edge of the pack. Or a combination of both.

The only info I have that says anything about ice thickness is this last image from Russian scientific institute AARI of the distribution of multiyear/old ice, dated May 29th:During the freezing season a band of multi-year and (I presume) thicker ice was transported all the way from the Beaufort Sea to the area where the melting has slowed down considerably. The influence of this ice on the final shape of the ice pack, and thus the outcome of the melting season, should not be underestimated. Both in 2010 and 2011 a relatively large area of ice just north and west of the Chukchi region managed to survive long enough for freezing temperatures to take over in September. I referred to this phenomenon as The Arm in 2010 and had something about to say about it in the final analysis of last year's melting season as well.

However, the amount of multi-year ice on the Pacific side of the Arctic isn't the be all and end all of final ice pack contours, as was proven in 2007. The ice was probably thicker back then, but it didn't matter one bit for the shape at the minimum. All of the ice on the Pacific side of the Arctic had been melted or transported toward the Atlantic. During my research for the recent Ocean heat flux blog post, I came across this 2009 research paper by Woodgate et al .: The 2007 Bering Strait oceanic heat flux and anomalous Arctic sea-ice retreat (a summary of which has been posted in the Papers section earlier this week). This paper shows that due to atmospheric patterns a large amount of oceanic heat was transported through Bering Strait in 2007, which played a significant role in the extent and area records that were set at the end of the melting season.

Here are a couple of excerpts from the paper that show why heat transport through Bering Strait, and thus SSTs in the Chukchi Sea are important:

We suggest the Bering Strait inflow influences sea-ice by providing a trigger for the onset of solar-driven melt, a conduit for oceanic heat into the Arctic, and (due to long transit times) a subsurface heat source within the Arctic in winter.

Year 2007 yields a clear record-length maximum, estimated at 3.5 x 1020 J/yr from A3 data alone and at 4–4.7 x 1020 J/yr including a 10–20 m surface layer. Adding 1 x 1020 J/yr for the ACC yields a total heat flux of 5–5.7 x 1020 J/yr. This is almost a doubling of the total 2001 heat flux (2.6– 2.9 x 1020 J/yr), and 1 x 1020 J/yr greater than the previous high in 2004 (4.3–4.8 x 1020 J/yr).

How relevant is this amount of heat (3–6 x 1020 J/yr, i.e., 10–20 TW) in the Arctic? This much heat could melt 1–2 million km2/yr of 1 m thick ice.

Later this week I'm writing a blog post that - among others - compares this year's sea surface temperatures to those of previous years. But I can say in advance that the SSTs are much lower this year in the North Pacific, Bering Strait and Chukchi Sea. As we all know some pretty extreme weather conditions this winter caused a huge amount of ice to form in the Bering Sea (see blog post), and although that ice melted out very quickly once the melting season got underway, it very well could have that buffering effect we speculated about at the end of the freezing season.

To give you an idea, here's what SSTs in the Bering Sea currently look like (from this blog post by Bob Tisdale):

I'll be writing more about this some other time as well.

To conclude: As things currently stand I think a combination of thicker ice and relatively low sea surface temperatures will turn the Pacific side of the Arctic yet again into a stronghold. It might very well prevent new extent/area records, although weather patterns are still the main factor, especially towards the end of the melting season. A minimum that is reached two weeks later rather than earlier, can make all the difference.

Or will these holes in the ice pack in the Beaufort Sea and in the Chukchi Sea, just to the north of Wrangel Island, play a role as well? Yes, some of the holes are in the Arctic Basin and East Siberian Sea as well. I'm not sure exactly where those demarcation lines are (see regional map on Cryosphere Today).

UPDATE:

This just popped up here and there in the media today:

Ice delays Shell Alaska drilling

Heavier than expected ice in Arctic waters off Alaska will likely delay until August Shell's long-anticipated exploration drilling in the Chukchi and Beaufort Seas, a company spokesman said on Friday.

Shell, which wants to search for oil in what are considered remote but promising frontiers, had planned to start the wells this month, said Curtis Smith, a company spokesman in Anchorage.

Sea ice is "the number one reason we won't be drilling in July," Smith told Reuters. "At this point, we're looking at the first week of August."

While sea ice cover is sparse in most of the Arctic, ice off Alaska is thicker than in recent years, and that ice is melting fast, according to the US National Snow and Ice Data Centre.

Shell plans to drill two wells this year in the Beaufort at a prospect about 20 miles offshore, and three in the Chukchi about 70 miles offshore. Drilling must take place during the brief ice-free season, since federal approvals for the plans require that Shell cease all operations for the year by 31 October.

The schedule is especially tight in the Chukchi, where Shell must cease drilling into known hydrocarbon-bearing zones by late September, with top-hole drilling allowed after then, Smith said.

Comments

Thanks for reviving the discussion begun by
Artful Dodger | October 08, 2011 at 21:05
... since Typepad.com doesn't link properly to multipage posts, it will suffice to reproduce those comments here:

________________

Hi Bob W,

The 2007 sea ice retreat was made exceptional by warm water inflow from the Pacific to the Arctic. Tethered Buoys in the Bering Strait measured ~4 petajoules of heat entering the Chukchi sea. This is twice the normal heat influx, and equal to total solar insolation for the Chukchi sea over the course of the melt season.

Look at the distribution of sea ice throughout summer 2007. There is a clear focal point to the melt, the source of the heat bloom is the Bering Strait.

This paper provides more details (the AGU introduction is provided 2nd below):

"The causes of the 2007 record-breaking Arctic sea ice loss are not well understood. To investigate the source of the heat that melted so much ice, Woodgate et al. study the role of heat transported to the Arctic from the Pacific Ocean. The authors use observations from in situ moorings and satellite sea surface temperature measurements to quantify the heat flux through the Bering Strait into the Arctic. They find that a substantial amount of heat is transferred through the Bering Strait and that this amount is highly variable from year to year. In 2007, both the amount of water flowing through the strait and the temperatures were at record highs, the authors report. They note that the 2007 heat flux through the Bering Strait was twice the 2001 heat flux and was enough to account for a third of the Arctic sea ice lost in 2007."

What I have not seen yet is any discussion as to the cause of the exceptional heat transport in 2007. I wonder if it was associated with the strong El Nino that year? If so, is this a common pattern for other El Nino years, and should we expect a recurrence during the next El Nino?

Given the weak state of Arctic sea ice in 2011, and the near total loss of MY sea ice, another +4 PW Summer heat influx from the Bering strait could well spell the first ice-free Fall.

Or will these holes in the ice pack in the Beaufort Sea and just to the north of Wrangel Island play a role as well?

BTW, I meant those smaller holes all over the place, not the polynya right behind Wrangel Island, which is a regular feature.

Given the weak state of Arctic sea ice in 2011, and the near total loss of MY sea ice, another +4 PW Summer heat influx from the Bering strait could well spell the first ice-free Fall.

Absolutely. Given the developments on the Atlantic side of the Arctic, and the general state of the ice, another summer with peak heat (and volume) influx through Bering Strait, and we will approach that final million of area/extent fast.

What I have not seen yet is any discussion as to the cause of the exceptional heat transport in 2007. I wonder if it was associated with the strong El Nino that year? If so, is this a common pattern for other El Nino years, and should we expect a recurrence during the next El Nino?

ENSO, PDO... I will probably do a piece on this if I can find enough info. Here's a good March 2011 article from Climate Central.

This year's ice in the Beaufort Sea clearly isn't any stronger than it was in previous years. We had already received a hint when the NSIDC released ice thickness data from IceBridge flight missions over parts of the Beaufort Sea, and the current big polynya and very low ice concentration there seem to confirm that this region isn't going to put a brake on this year's melt.

Neven, thanks for posting about this, as it was something I was wondering about.

The open water in the Beaufort Sea is incredibly hot. Above 10C in some areas, and a full 8C warmer than climatology - completely off the scale of the OSTIA SST anomaly plot. So I was expecting that the ice extent would have declined faster than it has in that area.

The arc ice thickness (from your daily graphs page) and the Russian plot you cite above, both suggest that this is partly because there is thick multi-year ice on the edge of this open water, slowing the decline in ice extent.

So perhaps the somewhat thicker ice and high SSTs are acting to cancel each other out, so that the extent decline is neither particularly slow or particularly fast in the Beaufort Sea.

So perhaps the somewhat thicker ice and high SSTs are acting to cancel each other out, so that the extent decline is neither particularly slow or particularly fast in the Beaufort Sea.

I think I more or less agree. On the one hand, that polynya is quite big when compared to previous years. On the other hand, there is still a lot of ice hugging the coast. But I was expecting more resistance in the Beaufort Sea after this winter.

Don't you go for vaccation soon?

I'm going at the end of August. Still have to find a way to make sure I have a good Internet connection there. Wouldn't want to miss the minimum, now would I? What kind of a holiday would that be? ;-)

According to GFS in about a few days the weather will turn significantly cooler in large parts of the Chuckchi Sea and the East Siberian Sea.
Seen whether this will restrict the speed at which the ice melts there. (Assuming the weather will become cooler).

Regarding the update: consider the source. It's a press release from Shell - they have a vested interest in spinning any and all delays as being due to the ice conditions. After all, if the ice is nice and thick, then global warming isn't happening, which must mean it's safe to prospect for more oil, right?

From the data of NASA Ice Bridge can be found that the average ice thickness above 80 degrees north latitude off the coast of Greenland and Canada's 3.5 meters. During the summer melt of about 1 meter of ice. In September, will be 2.5 meters. The area of the ice about 1 million km2. So the volume will be equal to 2500 km3. The remaining ice to melt this summer (in theory). Although if the thickness of the remaining ice would be 10 cm, the volume of the remaining ice would be 300-400 km3.

Paradox, Neven,
Nothing is as it seems. That’s probably why you chose the nickname. What you hint at could very well be the beginning of the El Nino cover-effect. It could save the Arctic Basin ice. But the season can still pan out on 3,7 MK extent minimum. IMHO positive AO and low SLP doesn’t produce the results we knew a couple of years ago. The mid July lows bring SW winds over the Kara and Laptev Seas. Perfect for the Atlantic side to succumb to the high SST’s.
For today: watch how transport into Nares Strait is beginning in the Lincoln Sea. Not far from there, the big high is ripping the pack maze north of Ellesmere in SW direction.

Regarding the Chukchi, your argument of the harsh winter, leading to thicker ice, the low temperatures in the Bering, and the albedo effect working both ways (early low extent amplifies ice loss later in summer, but early high extent reduces ice loss later in summer) are compelling.

Still, now that the melting season is in full force, I wonder how much the reduced Being heat influx (10 TW 'anomaly') really matters in the big picture these days. For example, the Northern Hemisphere June snow anomaly alone adds about 1000 TW heat influx w.r.t. a few decades ago, and even if only a small amount of that heat makes it to the Chukchi, it could overwhelm the ocean heat influx.

Either way, the Chukchi seems to run only 50 k km^2 behind 'long-term-average' (about a week) schedule and some 150 k km^2 (three weeks) behind 2011. http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.10.html
Since the Chukchi was ice free for 2 months last year, this may simply mean that the Chukchi still has a 150 k km^2 "piggy bank" w.r.t. last year, which it will give out later.

Beyond that, the 'stronghold' may have to come from the Arctic Basin, where the battle between the positive anomaly from the West and the negative anomaly from the East would have to be fought.

It's going to be (again) a very interesting second half of the melting season...

Regarding the possible link between El Nino events and Bering SSTs, at least according to Neven's graph, 1998 holds the record for lowest SST. And we all know that that year was marked by a 'super' El Nino...
I did not do a correlation analysis, but I suspect that the El Nino - Bering SST correlation is low.

Thanks, Rob. I agree with what you say. In fact, I'm not sure at all about what is going to happen. I'm just basing myself on what I've learned from the last two melting seasons.

But if the PIOMAS volume numbers are more or less correct, warm water inflow from the Bering Sea may not be needed to break records. And like I say at the end of the post: those holes in the ice pack.

We are now going to get at least a week of dominating lows. I expect a lull in area/extent decrease, but am curious to see how the ice pack is going to look 10 days from now.

Clicked on it for the larger image--I was intrigued by the 'recovery' in anomaly for the CA, which I'm sure is a matter of ice being transported *through* the CA.

Kevin, if I've interpreted you correctly, you refer to this year's anomaly shooting back up to the ling-term average, right? This anomaly was caused by massive melt ponding all over the Archipelago, fooling the satellite sensor (happened more often in the past few years). But the ice is holding up pretty well so far, and so the anomaly shoots back again, with melt ponds draining, etc.

What makes the NWP interesting to me this year is that while for instance the ice arch in Lancaster Sound held up very long (until yesterday) it was actually stabbed in the back by melting and disintegration taking place on the inside.

Neven, it's not clear to me if we are on the same page here or not. I'm referring to the lower graph on the page, the one tracking just this year's anomaly. There was an abrupt drop about halfway through June, followed by a sudden recovery to above the mean, then a drop down to average, which is where it is now.

Is that what you mean, or were you talking about the multi-year graph?

That is the graph Neven is talking about and the 'recovery' is due to the loss of melt ponds and the problems they cause for the passive microwave sensors - this is what Bill Chapman at CT said:

In the meantime, at least part of what could be causing the apparent discrepancy is the problem the passive microwave sensors have in determining sea ice concentration from melt ponds. This time of year, this issue is particularly problematic as the melt season is in full swing in the southern parts of the Arctic. I've seen cases where it looks like the passive microwave derived sea ice concentrations (such as ours) underestimate sea ice concentration by up to 20%. From what parts of the CA I can see in the latest MODIS that are mostly ice covered, it looks like it is very slushy and has lots of melt ponds. These areas show up with a grey and/or bluish tint in the full color MODIS images. Another issue that can cause underestimation of the concentration in passive microwave products is cloudiness, especially optically thick clouds. My guess is that there is some open water already forming in the CA and it is obscured by clouds that we just don't see right now, coupled with artificially low concentrations from the melt ponds and clouds. My guess is also that this heavily melt-ponded ice is not long for this world.

Indeed, Christoffer. Let's see how this develops, as the red on the DMI SST anomaly map can quickly appear, disappear and reappear. There was some red and orange in the Bering Strait region a couple of weeks ago as well.

But this time I'm also seeing it on the other SST anomaly maps on the ASI Graphs page.

Mdoliner:
That conference being 2 year old, but "the rotten MYI" phenomen was debated on this blog, just as the Polarstern crossing the Pole July/Aug. also more or less concluded that the state of MYI is both thin (1-1,5 meter) and pretty rotten.
With that as background curtain we all await what Polarstern is up to this season!You may track the whereabouts of the german scientific ship and the frequent air and seatemps they are doing. Just this morning west of Svalbard they reported of -2,4 C, must be pretty much the coldest spot in the Arctic region lately!http://www.sailwx.info/shiptrack/shipposition.phtml?call=DBLK

Neven:
WiFi is "almost as important" these days as a sucessful harvest back in the Viking era in Greenland 900 years ago... (One might speculate how fragile our community would be in case of a sudden temperaturedrop or rise of 2-3 degrees!? )

At Churchill, Manitoba,Hudson Bay, "Polar Bear Capital of the World", they have today been reporting 31 C for 5 consequtive hours, just "smashing" the record maximum temp for this date, set 2011, with roughly 11 C!!
And they got Polar bears at that place...almost unbelievable that is. Someone call 911...

On the DMI temperature map almost the whole arctic is shown at >0C levels. But in a few areas sometimes <0C levels are reached, and these areas always seem to have wide cracks between the floes - could that be excessive melting driving the temperature down to the freezing point of ocean water?

How often does such lowpressures take place in the Arctic during the summer? And will they also be an extra meltdown force, churning up the fast ice, pushing it around, mixing in saltwater in the snow and also perhaps leading both hot air and water from more southern latitudes into the colder Arctic, north of 80 degree?!

I think cyclones in polar regions are mostly relatively weak and short lived. But who knows, if SSTs will rise, we could see some interesting stuff, like: "Arctic storm Andrew developing eye on North Pole."

AmbiValent:CT appears to have reported a double century (-240k), with the new area of 5.358 m.

Correct. That's the the second largest one-day decrease this year. That area of 5.358 million is lower than the minimums seen in 1979, 1980, 1983, and 1986. (2012 is safely in first place for the time being, more than half a million square kilometers ahead of second place 2011.)